Glyphosate, the main chemical in the weed-killer Roundup, is one of the most popular herbicides on the planet, but newly unsealed court documents suggest that Roundup’s manufacturer, Monsanto, may have written at least some of an academic research paper used to demonstrate glyphosate’s safety.

The documents — including internal Monsanto communications and correspondence with the Environmental Protection Agency — were turned up as part of an ongoing massive lawsuit alleging that the agribusiness giant failed to warn consumers that exposure to Roundup could cause cancer.

The safety of glyphosate has been debated for decades, with Monsanto long claiming that the chemical poses no risk to consumers. In 2015, the International Agency for Research on Cancer (a branch of the World Health Organization) classified glyphosate as “probably carcinogenic to humans.”

In one unsealed email [PDF] from 2015, a Monsanto executive suggests a “less expensive/more palatable approach” to an in-the-works plausibility paper: Only use experts for portions of the report that are in contention, and then have Monsanto staff “ghost-write the Exposure Tox & Genetox sections.”

“We would be keeping the cost down by us doing the writing and they would just edit & sign their names so to speak,” explains the email written by Monsanto executive William F. Haydens.

The email also seems to imply that Monsanto had previously ghostwritten portions of one other paper, noting that this is “how we handled Williams Kroes & Munro, 2000.” In 2000, three researchers by those names published a report in the journal “Regulatory Toxicology & Pharmacy,” concluding that “Roundup herbicide does not pose a health risk to humans.”

Another email suggests the Monsanto worked with a former deputy director at the EPA to quash research from the Department of Health and Human Services related to glyphosate.

Monsanto executive Dan Jenkins said in an email [PDF] in 2015 that then-EPA deputy director Jess Rowland had told him that , “If I can kill this, I should get a medal,” referring to the Department of Health and Human Services review.

After the review failed to take place, Jenkins wrote in another email that soon-to-retire Rowland could be a good resource for the company in the future when it came to glyphosate.

In a motion [PDF] to compel the testimony of Rowland, the plaintiffs argue that “Monsanto enjoyed considerable influence within the EPA’s OPP, and was close with Mr. Rowland… Monsanto’s influence, then, will be crucial to the analysis of the EPA’s findings and conclusions even as the parties litigate this first phase of general causation.”

Monsanto tells the NY Times in a statement that “scientists did not ghostwrite the paper” and that the research “underwent the journal’s rigorous peer review process before it was published.”

The company also reiterated that glyphosate is safe.

“Glyphosate is not a carcinogen,” the company said. “The allegation that glyphosate can cause cancer in humans is inconsistent with decades of comprehensive safety reviews by the leading regulatory authorities around the world. The plaintiffs have submitted isolated documents that are taken out of context.”

Additionally, a researcher named in a Monsanto email tells the Times that he would not publish a document that had been written by someone else.

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